Telescopic dumping truck



Dec. 22,` 1953 A. R. PHELPs TELESCOPIC DUMPING TRUCK` g1 Sheets-Sheet 2 Filed Nov. 28, 1950 IN V EN TOR.

44H17 ufR. Phez Dec. 22, 1953 A. R. PHELPs TELEsCoPl-c DUMPING TRUCK 4 Sheets-Sheet 3 Filed Nov. 28, 1950 INVENTOR.

helps Knuf.

Dec. 22, 1953 4 sheets-sheet '4 Filed Nov. 28, 1950 INVENTOR. R. Ph @I Ps Fi 'J4' rv'hur A 4Q Fig-.12.

Patented Dec. 22, 1953 UNITED STATES PATENT CFFICE 7 Claims.

This invention relates to a telescopic dump truck and has, as one object thereof, the provision of an aligned center guide and center drive actuation means whereby the telescopic sections of the dump body will nest progressively in the desired sequence without canting, yawing. or sticking.

For many types of hauling, the telescopic dump truck long has been recognized as possessing a decided superiority over the conventional pivoted dump truck. This superiority stems from many factors, among which may be included the following: (1) With similar volume carrying capacities, a much lighter construction can be utilized in the telescopic body since the dumping operation involves a longitudinal carrying of the load rather than a pivotal lifting thereof. (2) Because of their simple operation and lightweight construction, much larger telescopic bodies are feasible. Thus, a given volume load will require fewer trips. (3) Again, because of the lightweight construction, a telescopic body imposes less strain on the trucks power take-01T mechanism during dumping. (4) A telescopic body can discharge into elevated hoppers and troughs since the discharge end is maintained level during dumping. only fall over the back of each telescopic section progressively rather than Slide down the inclined length of the entire body, a nicer control of the dumping operation is possible. This is not to imply, however, that the conventional telescopic dump truck is entirely free from all functional disadvantages, for it is not. In fact, I have come to recognize these disadvantages and my inventive efforts have been turned toward a correction thereof in a manner now to be described.

The conventional telescopic dump body includes a plurality of similarly shaped body sections, arranged one in front of the other in order of decreasing cross section, and mounted on a truck or trailer chassis. Usually, the back section carries a tail gate and is fixed to the chassis whereas the other sections are mounted for longitudinal movement into and out of a nesting (5) Since the load need relationship. Thus, when a load is to be dumped,

from sticking, wedging, and canting. Furthermore, the sequential nesting must always take place so that each section is completely telescoped before the section just forward thereof begins to telescope. This requirement will be explained with reference to an example.

Assume, for a moment, that a telescopic body is loaded with a lightweight aggregate, dry sawdust, grain or some other light, bulky cargo. Further assume that one of the middle body sections sticks, cants', or otherwise refuses to nest before the next forward section begins to nest. Obviously, that portion of the load which is carried forward of the immobile middle section will push on and tend to compress the load in the middle section. As the telescopic operation continues, the light, bulky cargo will begin to hump up and, eventually, a portion thereof will spill up and over the sides of the body. If, on the other hand, none of the sections stick or wedge and the sequential nesting progresses as desired, the rear section will discharge; then the next section in front thereof will nest and discharge; and, eventually, the most forward section will nest and discharge; all without spilling or compressing the load.

Various patentees in the telescopic dump truck art have recognized this' prime requirement and have made provision therefor. For example, one such typical provision (see U. S. Patent 1,794,318) utilizes a series of latch bars which lock each movable section in the expanded position. Thus, each section is made integral with the section immediately in back thereof. When a load is to be dumped, the rearmost latch bar must first be unlatched or unlocked. Thereafter, and sequentially, the second section nests in the rear section; the third section is unlatched; the third section nests; the fourth section is unlatched; and so forth. This type of sequential nesting is termed positive lock because each body section must telescope fully before the next forward section is unlatched. No spilling is possible with a positive lock mechanism because, should one section stick or cant, the entire mechanism is rendered immobile.

I have become dissatisfied with positive lock mechanisms and have turned my inventive efforts toward a different soiution to the sequential, non-sticking problem. In so doing, I have found there are a number of factors which cause a telescopic body to cant, wedge, bind, or other- Wise deviate from the desired nesting sequence. These factors include: (l) Loose material such as pieces of rock and particles of sand or grain tend to lodge between the bottom and side walls of adjacent nesting sections. 'I'hese inhibit free movement of the sections over one another and are cumulative in their effecteach load adding more particles. Consequently, a periodic cleaning of the nesting structure is required. (2) The conventional telescopic body is actuated by twin chains, cables, or hydraulic mechanisms located one on each side of the body sections. This is a disadvantage since,..sho.uld one sidof'a sec-.- tion move slightlyl faster o1' furtherthan theI other side, a cant or yaw takes place and that particular section tends to bind and hang up.` (3) 'I'he conventional telescopic bodyf'Illini-esk7 011:. twin guides disposed down the sides of the truck or trailer chassis. These guides servetio` inhibiti lateral movement of the Sections. They. alle..v however, less efficient than one central guide. Thus, any ofi-center loading or any Cantin-g: of a section tends to cause.- a bind on two spaced side; guides whereasi onefcentral. guida elixm'natee.;V this'` disadvantages. (4i-)sf Similacyf. the ccnvenre tional telescopic. body." is: iabricatedr; from: lig-hte weightl met'aisfsucin as-:relativelyi thinesheet steek..

lfepeateciA use; bend. or.; warpisnchs. thini secr tions. If two; guidesa are utilize.d;. any; change: in the-lateral; dimension off ai sectorn wilh cause it..to.:stickf` or wedge.A Ifj. however; oneecentral. guidea ist utilized;A such: dimensiorn changes` leave?V the-telescopic..movementeuninhibited..

Having: set. fertili those:V factors; which; cause: the i oonventionals.telescopic. body: tircant wedges. bind; on othenwise deviatezfromithe: desired-neste insa Sequence. I; shailf. set fortin the: venons Structural. details; with. which; Ii overcome theses ;l

factcraand disadvantages; Thesis structuradgdeftaila,V then;A stem diinctl'yr frnm: my,T inventive.. efrortsrto providey a novel; and: different: solution.` to.;` the sequenti .nesting1 problem.. They arezini directzcontrasktmtheposituealoclci solution. Aca

ccizdinslitY theyfal'soz-de eathe obictszof my.l inew venticrn (fl) lhave secured ai.peripheral.- skirt-z abfruttheiwa'llsaand: bottom on each@ body. section.. This` skirt: sidabiy engages an'dc servesl to. space-1.,. companion". nesting sections'. to; define; therebeeA tween a chamber. Thus, when loose material: terrdsatc; lodge; between companion.:sections',l it is collected: in this: chamber.; and when; next; thef body.- is; extendei. the-askint: sweeps the chamber: clean.. (2) l'i utilize but?` one.I central. gnidef tow provideg againsirilateral' movement: and; to guide; the;1 longitudinal movement. off these; sections;. This` is.. on' dennite' utiiity., in` inhibiting binding1 and Gauting-or; yawing.. (3P If' provide but one: centr-al: actuationi nieansuand. the' push thereoni 5i is-axially aligned' withi the centrailguide: Such: actuation is: cumulative with. theguide function".` ininhibiting bindingV andi wedgingf. (It) Il proA vide inadvertentn nesting, as Whenam' emptyf truck isl returning to-pickup-a load?, byA positivelylocking both: tha t'ailf gate-l and`- th@ telescopic sectionsfagainst longitudinal'-movement'.I (55" Icorrelate thenateofnesting'offthe sections? torth-eigroundspeediof thetruclcby driving theactuation` mechanisin fromL the: truck:- transmission.

Thus, when bituminous concreteorcthermaterial is to vbe spreadover'a largearea, thegdesiredcoat thickness can beregulated" by: adjusting the'- groundlspeed of thetruckfand the rateofinesting1 or dumping; simultaneously.

These andv other obj ects-:andf' advantages of? invention. willbe hereinafter: set-1' forthv in theafolilowing detailed description: taken in-V cong'un tion withrthe accompanyingdrawings, inwhichzv Figs; 1, 2, and. 3 are relatedlperspectiveviews' 7 i showing a typical telescopic dumping operation as effected by my invention;

Fig. 4 is a top view, partially broken away and ioreshortened, showing the tail gate latch and a portion of the actuation mechanism for telescoping and extending the various sections of rny telescopic body;

Fig. 5 is a broken detail view, taken substantially on the line 5 5 of Fig. 4showing, one oi thev track supported rollers which cannv; the forward" end of-` each telescopicv body section;

Fig. 6 is a broken detail view, taken substantially on the line 6 6 of Fig. 4, showing a side View: Orione. on the rollers and also showing a portion of the peripheral skirt which extends about the-rear-of each movable body section;

Eig.. 7. is; anothenbrcken section view, taken substantially on the line of Fig. 8, showing thatf-portin of the peripheral skirt which slidably engages the side wall oi the telescopic section?. companiorn thereto;

Figi.. e;v is,i az side? View; partially broken: away.: andi foresholttened, showing? telescopic *.boiit?Y andfagportioniogthe :actuation: ineehaarrismithence` ford whereby;Y the conventional: tru ein transmissioni iswoperatively ioinedrto nryfantnation-mechansmi to correlate the rate of nesting to the vehicle enound sneedfwheni desireds:

Fig. 9; is; a brokenL section.: view;. taken; stantiallyf on.; thezlineee-fofs Figi .4; showing@ one; of: the. sliding snoesi whichiis.an.integral1partiof" my'` medial. guide;:V means: for: restricting: lateralz movement of; each; bndy.: section;

10. isy a: schematic; wiring; diagrama also: showing` a particuli; of? my,r actuation". mechanism and; indicating. diagrammatically; the; structurer` by whichr Ii controlL theinesting: andi extending` of.P myf telescopic: body' Figs. 11 1TBare..-re1ated sideeviews;i pantially: broken; awaw. indicating the? two operative pesif-i tions of: the.;camefacedshowhich: automatically* unlocks the .tailigate andi releases: the telescopic: eotions-jusin priorftoithe start ofi arresting operaioni;

Fig. 13 isi detail' vie-w; partiallyibrokeni away; anditalien'.substantially,4 onzthe Lline. I3'-J$ offFigf;

11, and4 more=parfticularly indicating:` the slida'bieiY andfthef lockfblockfto the-endless chain4l loyfrneansfof*l which I actuatemy` telescopicl body:

InFigs'; 1, 2,' and 3g Ihanfeshowninytelescopice body' I mountedl on a trailer chassis` 2^ pulled". byr tractorV 3'. 'Iliese` figures indicate; sequentially; threestepsina typicaldumpingpperation. They.v also.. show that. the rearmost. body section 4 is.

.l fixedl to. the. trailer. chassis.. 2. whereas. ail' body,

sections.forwardtherecf. arelongitudinally moi/af ble.. Furthermor.e in orderV tdcompletel'y: empty. themost. forward body section... 5*,.1 have.. disposed therein; an obliqueV floor. 6.. This obliquefflaon- 6.2:

.- extends. from; theftopf front; to.;t the bottom. rear.'-

maximum angle of repose of all those materials commonly to be carried by my telescopic body.

Progressing from the rear to the front of the body I, it will be noted that the various sections thereof are of complementary shape but oi decreasing size. Thus, the rearmost body section 4 is the deepest and widest of all sections whereas the front section E is the least deep but is the longest of all sections. This tapered disposition of the body sections is necessary to a correct nesting or telescoping function. Furthermore, each section must be somewhat longer than its next rearward mate since, when the body is completely telescoped as shown in Fig. 3, the rear faces of all sections must be in vertical alignment to completely empty the body.

' Progressing now to Figs. li, 6, and 7, I have therein shown, in enlarged detail, those elements which are in operative contact between adjacent body sections. Thus, each body section has two side walls l joined by a bottom wall 8. Fig. 4 would appear to indicate that the bottoms and walls of adjacent members actually contact one another. This, however, is not the case. Rather, I secure a peripheral skirt 9 about the bottom t and side walls 7 of each section. This peripheral skirt is perpendicular to the respective walls and is in sliding contact with the inner surfaces of the next adjacent section. For example, Fig. 6 indicates the manner in which the peripheral skirt 9 spaces two adjoining bottom members 8 and Fig. 7 indicates the manner in which the skirt spaces two adjacent side walls 1.

As best shown in Figs. 6 and 7, the spacing provided by the peripheral skirt S deiines a chamber I0. This chamber is U-shaped since it extends about the three sided periphery of each body section. Furthermore, since the skirt 9 moves during each telescopic nesting of the body sections, the chamber I is expansible yet the front side thereof is open. I deem this chamber to be of critical importance since, should material lodge therein during a nesting of the body sections, (such inadvertent lodging is almost impossible to prevent) the peripheral skirt 9 acts as a scraping lip to clean the chamber. The conventional telescopic body fails to provide such an open-faced chamber and, when loose material such as pieces of rock or particles of sand or grain lodge between the bottom and side walls of adjcent nesting sections, the free movement of the sections over one another is inhibited. Furthermore, this loose material accumulates as load after load is dumped. If the driver fails to clean the body, the accumulation may render the nesting structure inoperative. With my selfcleaning chamber, however, material does not so accumulate and repeated use with little or no attention is possible.

Each section of my telescopic body is supported at the rear thereof by the aforementioned peripheral skirt 9 and at the front thereof by two spaced rollers Ii which ride on angle iron tracks I2. The rollers II are journaled in a U-shaped member I3 pendent from a main cross frame lli. The U-shaped member I3, in turn, carries a safety catch pin I disposed below the track I2. During operation, the various rollers i i Vcooperate to carry most of the weight of the load in each body section and the catch pins l5 function only if a section tips inadvertently. Furthermore, the pins I5 and member I3 are spaced laterally from the chassis proper so as never to make contact therewith. In other words, this structure does not guide the sections to inhibit lateral movement; v it merely carries the load. In this manner, I allow for a slight lateral dimensional change in each section. When it is remembered that telescopic bodies are constructed from relatively thin sheet metal and are subject to repeated bending stresses, the importance of this lateral spacing becomes apparent.

The various sections of my telescopic body are nested and extended by an actuation mechanism 'which includes an endless chain I6 or a similar cable, wire, rope, etc. Whichever structure is utilized, I prefer to dispose the same longitudinally down the center of the tractor chassis 2. To this end, two angle iron guides II are secured to the tractor chassis in spaced relationship (see Fig. 13). The chain, cable, or the like rides between these guides and is reaved over two spaced sprockets IB and I 9 journaled under the front section 5 and rear section d, respectively. The sprocket I8 is an idler sprocket and the sprocket I9 is a drive sprocket.

The .angle iron guides I'I serve yet another function. Thus, a pair of shoes I la slidably contact the outer faces of the guides Il. This sliding Contact should be contrasted with the spaced relationship of the side roller structure. The shoes ila are pendent from the aforementioned main cross frame I4 and. a pair of shoes are associated. with each telescopic section to carry the front of the same. The guides II and shoes lla, together, define a central guide inhibiting lateral movement and guiding the longitudinal movement of the telescopic body. Thus, as heretofore pointed out, one central guide is far superior to two spaced side guides since the former will serve to inhibit canting and yawing without binding or catching during actuation.

Returning now to the drive sprocket I9, rotary motion is transmitted thereto through a worm gear encased within a housing 20 (see Fig. 4). The worm gear, in turn, is driven by an articulated shaft 2 Ia. This shaft 2 I a is driven by a second `articulated shaft ZI?) through a chain reversing mechanism housed within the box l2Q. Turning new to Fig. 8, a bevel gear 22 drives the shaft Bib and, in turn, is meshed with a similar bevel gear 2t. The gear 23 is journaled inthe chassis and derives rotation from two more similar bevel gears 24. Thesecond of these latter gears is keyed to a main drive shaft'25.

In the right hand portion of Fig 8, I have shown a housing slightly'forward of and to the side of the conventional truck selective speed 'mechanism or transmission housing 2l. Furthermore, I have shown an operating handle 28 for engaging and disengaging the mechanism within the housing 2% and I have indicated that the main drive-shaft 25 is driven from within this housing. In further explanation, the housing 28 shields the conventional power take-olf mechanism so often associated with large trucks and tractors. That is to say, a power take-olf shaft engages the tractor power imput shaft within the transmission housing 2l. This power takeofi shaft drives the gearing within the power takeoff mechanism housing 26. Thus, the speed of rotation or" the' trac-.tor engin@ is imparted to both the tractor power take-off shaft and the mechanism Furthermore, this structure iunctions to correlate the speed of rotation of the mechanism 26 to the speed selected to drive the tractor 3 over the ground. The handle 28, on the other hand, will either engage or disengage the main drive shaft 25 with the power take-off mechanism housed in 26. Thus, the

'ldivesshat 1^ 2.5 @turns the.A various' bevel gears f1.2.

:a .fselected' zone. et-a.v 4nesting :chain vand 'sprocket mechanism :3E 1and-.an.eietending*chain and '-.slzrrocket -mechanism .-34., 3 La, -.the `sprocket A134e representing@ reversi-ng sprocket. YA selector fork 32 -isfL-pivoted at :33 #and carries -a sleeve rwithichffslida-hly encompasses the -articuiated :shaft Z lb. The lower end of the :fork Y32,:inturn,fslidably-engages the :doublecollar'fto pivot as ethe .oellarwmoves The double xcollar `35 is slidably ,carried-"by the piston rod 38 -butfisyconstrained or movement @therewith by'twocentering springs 36 which :hearV on the twinflanges l These nanges-zare-seoured'tothe `piston'rod 'A @double-acting f .pneumatic J=motor -39 reciprocates thefpiston--38wand the .piston rod'v38. Thus,

Whenethejpistonra shifts-tothe right inFig.V 1-0,

the selector oskf-Szlcauses thecoilar-:Si to' engage the extending chain and sprocket lmeclfianism 34531 a to rotate-'the @articulated :shaft fZ-l a in a xdirection to :extend the telescopic body sections. @n theother hand, when the pistonafmoves toi-the leftfthefselector liork A3i .reverses-:the posi-- tion r'ofthe collarf 3--to fengageethe meeting ychain @and sprocket mechanism e30. This movement :disengages fthe'xmechanism .3;|-3Ia '-an'd causes the articulated shaft-11:21u -to-.rotate in =the .opposite direction solfasfto inest i `the telescopic body sections.

=With further reierence tto Fig. 10,-I.have indicated schematically fthe-:electric Wiring rdiag-ram and -mechanism by means-of which Lcontrol the *reciprocal movements of .the double-acting -pneumancino/s011139. Thus, I Vhave shown two fmotor vcontrol-'Valves 40 Iandr! 1havingspringbiased solenoid actuatorsa'and 44a, respectively. The motor-control valves -fsupp1y andexhaust .fluid :towand from `the /opposite y:sides of thepistona. Accordingly, rthe-:electric 'wiringwinust` include la :batteryf an f ignition switch-43, Aa selectorfsWi-tch 4Mfand two Llimitand twordireetionswitches. rIhe directionr switch #45. is flocated in-fthe'cab'Jof-the i tractor z3 -While :the :direction switch 46..is located 'onf the rear` rloody :section 4' as show-nin Fig. 8. zTheftwof spring biased :limitzswitches il'anded, iin turn,.zare located Afunderv the :bottom`wall of the frontfsection v5"and :the'next to the last section ftsee Ai4)A so 'as "to `becontacted =atf-the1respec .tiveeitreme :limits-.cica nesting .and .an extending operation. During an voperative cycle -of this mechanism and 'by 'Way of example, 'the ignition switch '43 4is closed,`the selector switch '44. is moved "either-to rthe right to fselect a cab actuationstationfor the .left to select the rear section actuaf'tionstation, rand the ldriver or Ioperator.stations .fhimselfaccordingly lf the vrear stationhas been seleotedfthedriver stands (beside the .rear section Land-reachesup to .actuate .theswitch v`In one position of this switch l(to theleft) the solenoid 40a will .be-energizedto actuate .the control -valve .Ml-and `move .thepiston- 38a vto the righty i( see Fig. .-w). Sl-nthe other position of .the switch '46, the

ton )38a zito 1 the deft. :When vr.the f. telescopicffbndy sections-.reach .ione limit offrmovementptheicorre- Vspending limit .fswitch'l or AB-:isfopened to break .the circuit mated-theretd Thusywhen thevsections-ane iwllysnested, the. limitiswitchel'l vsiopen .so-the chainreversing mechanism `.can :move only -to. extend .the sections. Similarly,` when the :body .sections -are..fully.extended, Vthe limit '-switc'hsd 'isopenand vthe mechanismof Eig. 10 :is-operative-only-to move the reversingnmechanismr-.to thenesting-position.

. In Figs. .11 to 15.,zinolusii/e,` vI.-fhavesshownothe structure `which servesftosr lock-.thefbody sections .in fextendedfposition. At :the .lsameqtime this structure serves rt.or1atch and ..unlatch the tail .ga-te 12 Wh-ch is-piyote'dion the-rearsbodyseetion 4. II-oi 'this-.end lascam-.f-aced shoe-.49 i Kcarriesfa sloping Ecai-r1.-fa :e Maand. is secu-red betweenitwo linkspf .the'chain-.t A-,heayy L-bar-isxwelded #botlrfto the .medial-portion .of-.theirontisection Aatonenf-the .-maincross .members .M `and totwo :plates S2-to .thereby ldenne .a 1hollow chamber-53 see'liigs. .8f-1.1, and. .1.2) The .hollowichamhen Ais traversedJoy anv elongated .bolt B4-.secured lby .'nutsfto. the .aforementioned-.plates52.. l The shoe 4.9,. in turn, :is ,pierced by .anaxial aperture-5.5 :which yslidaloly. .encompassesthef .boltf .5e-Sto gnide -the Yshoe for Ylongitudinal rmoizenfien'tbaol; and forth -Withinmhe hollow chamber b'3. .'husr as thechain I6 movesftheshoe i9 .iswireeto move .between the two .,respectivepositions Shownln Figs. 11 and Y12. AIntherpositionof`E!ig.'ll1l.,f1the shoeig' bears on the .right .hand platel52 and .the telescopicbodysections will .move to 'the extended position. .In the-.position ofFig. 12,the.shoe bears iin the .lefthandfplatez and the' telescopic .body sections WillLmove to a-nested position.

The .side Walls .of -the .hollow chan-iber'BB'in- ,clude .two :plates 5B and 5'! having Yvertical .slots "53. and` V59, respectively (seeFigylBl. 'I'.heslo'ts 58and159 accommodate :the vertical mo'vement'o'f -two ,pins ED and "Si carrying vthe irecipro'clly mounted keepers `(i2 'and 63, respectively. Thus, both .offlthe pins 60 .and `6 i. extend'into"'the .hollow chamber .53'for cooperati've engagement With the cam face 50. When the Shoe 49 'moves'to'thelet these two pins are lifted vertically 'in 'their' respective slots to .liftthe keepers '62 'and63 'Whichare 'secured thereto.

"'Referringnow' to Figs. 14 and 1`5,-the" function ofthe 'keepers 62' 'and 63 'will be explained. "The `kee' p'er.`62 coacts With a catch B4 and'thekeeper 63 coacts with aflock block 65. When th'et'e'lescopic bodysections are fully extended, vthe keeper'V S3 drops down 'behind l:the Vlock 'block "'65 land holds the chain i 6 to prevent' an inadvertent nesting. Similarly, .the catch'l is constrained for longitudinal movement by'means of .a sl'otlBfB andis spring rloiased by thetension spring 61. An elongatedrod B8 .is secured to thecatchM-and this rod .articulatesanterliorly with across Soar VB9 (seeFig. 4). The cross`.bar`69,.inturn, carries apair of ycatches T0 which cooperate .with the pins Il carriedby the aforementioned tail gate'z. 'As is-conventional, the Ytailgate.ispivoted at 'its upper .end `solas to' swing open When .a 'load '-isto'be dumped (see'Fgsl 4v2 .and'3) v 'Returning .now to Figs. 14 arid. l5, as v.the chain TB moves toan extending ,position (to the right i11"1ig."14`), the keeper '62 engages the catch'id and mo'ves'it longitudinally against A'the'orce .of the 'tension spring B1. This movement causes the cross `bar 'B9'. anditail gate catches'l 'to engage thetailgate'ipins Tl and 'lok the tailgate 'securely in place. Similarly, when the chain i6 moves to nest the telescopic body sections (tothe left in Figures 1l, 12, and 14), the rst two inches or so of travel of the chain do not move the body sections but rather move the shoe 49 from the position of Fig. 11 to that of Fig. 12. During this rst two inches of travel, the cam face 50 lifts the pins 60 and BI. vThe pin S0 allows the keeper 62 to clear the catch 64 and unlock the tail gatecatches l0. The pin 6l lifts the keeper B3 vertically to clear the lock block 65.

In the operation of my telescopic dump body, let it be assumed that a coat of bituminous concrete is to be spread over a large area road bed. With the tractor and trailer in position over the road bed and with the tractor engine running, the ignition switch 43 will be closed (see Fig. l0) Accordingly, the driver will move the selector switch 44 to select the cab operating station as defined by the cab switch 45. Thereafter, the handle 28 is moved to place the imput shaft of the selective speed transmission 2'! of the truck in operative engagement with the power take-ofi mechanism 25. This will correlate the rate of nesting of the telescopic sections to the truck ground speed. For example, if a thick coat of bituminous concrete is desired, the driver will place the tractor transmission in compound low so the ground speed of the tractor will be slow. If, however, a thin coat of bituminous concrete is to be spread over the road bed, the driver will place the tractor transmission in second or high so as to increase the ground speed and spread a thinner coat. In either position, the rate of nesting varies directly as the tractor engine rotational velocity.

When the load is ready to be dumped, the driver actuates the direction switch 45 in the cab to move the double-acting motor 39 and the selector 32. Such movement joins the articulated shafts 2m and 2lb across the nesting chain and sprocket mechanism i3!! to begin the nesting movements of the body sections. Thereafter, as the tractor and trailer proceed over the road bed, the telescopic sections slowly nest and a thin (or thick) uniform coat of bituminous concrete is spread.

Nesting of the telescopic body sections proceeds as follows: The power take-ofi mechanism housed i112@ rotates the drive shaft 25, the bevel gears 24, the bevel gears 25 and 22, and the articulated shaft 2lb (see Fig. 8). The articulated shaft lbdrives the articulated shaft'2ia across the nesting chain and sprocket mechanism 30 housed. within the chain-reversing box 29 (see Figs. l0 and 4). The articulated shaft 21a rotates the drive sprocket I9 via the worm gear 29 to move the chain i6 to the left in Figs. li and 12. During the first two inches or so of travel, the shoe 43 slides over the bolt 54 and the cam face 50 engages the pins 6E! and 6l. These pins lift the keepers 62 and 63 to perform two functions. The iirst function is to unlock the telescopic sections by clearing the keeper 53 over the lock block 65. The second function is to release the catch 64 to unlatch the tail gate catches lil. Thus, the tail gate is unlocked and the body sections nest, sequentially, as the left end of the shoe 49 contacts the left end plate 52.

The medial push of the shoe 49 on the left end plate 52 moves the front section 5 to the left (see Fig. 8) by means of the L-bar 5I. Thus, the medial under portion of the front section is pushed rearwardly and, due to the relatively friction-free sliding contact of the nested body sections, the rearmost movable section begins to nest in the fixed rear section 4. As this nesting takes place, the load carried by the section 4v begins to spill out through the tail gate 'l2 (see Fig."2); In sequence, the various body sections nest in one another until the front section is completely telescoped as shown in Fig. 3. -At that time, the front section 5 empties completely due to the oblique disposition of the door 6. It will be remembered that this floor is disposed at an angle exceeding the angle of repose of the materialto be hauled. I have found that an angle of substantially 45 will serve this purpose. While I have selected a spreading operation to demonstrate one typical sequential operation of my telescopic dump body, it will be obvious that a load can just as easily be dumped while the tractor is at rest. Thus, a majority of dumping operations do not include a simultaneous spreading of the load. Rather, the tractor and trailer are stationed adjacent a dump area and the load is dumped in a single mound or pile as shown in Figures i, 2 and 3. Such an operation differs from the aforementioned spreading operation only in that the tractor transmission is placed in neutral. Thereafter, the telescopic body sections will nest, sequentially, as has been described but the tractor will remain at rest.

t is further to be noted and in accord with the objects of my invention, I have provided the peripheral skirt il extending about the rear of each telescopic section. This skirt is in sliding contact with the section companion thereto and serves to space the bottom and side walls of the companion sections to define the aforementioned chamber lil. This chamber, it will be remembered, renders my telescopic body self-cleaning to sweep out any material which may accumulate between the walls of the companion sections. Furthermore, I have guided the longitudinal movement of my telescopic sections and have inhibited the lateral vmovement thereof with but one central guide. -This guide I have aligned with the actuation mechanism so as to materially reduce any chance of canting or yawing during ar telescopic' operation. Thus, I have solved the sequential non-sticking problem without resorting to a positive lock mechanism. The cumulative effect of these novel structures is to correct the 'aforementioned disadvantages of the conventional telescopic dump body while, at the same time, preserving and amplifying those factors which make the telescopic body superior to the conventional pivoted body.

I claim: l.vr In combination with a motor vehicle having a selective speed transmissionand carrying a plurality of telescopic dump body sections mounted for longitudinal movement into a nested relationship, a tail gate movably mounted upon the rearmost body section and having a catch means selectively for latching and unlatchng the same, and actuation means engageable serially with said catch and with the most forward body section to unlatch said tail gate and nest said body sections, sequentially, said actuation means being operatively joined to and driven by said selective speed transmission to correlate the rate of nesting to the vehicle ground speed when desired.

2. In combination with a motor vehicle having a selective speed transmission and carrying a plurality of telescopic dump Vbody sections mounted for longitudinal movement into a nested relationship, a locking tail gate movably mounted upon 11"' the rearmost body. section.: A.catch means sprilg. biasedfto a release position and. movable to. a, latch position. in which. said tail. gate locked; guide means engaging the medial under side of said body sections to guide the longitudinal movement and restrict the lateral movementthereoff. and actuationmeansincluding: acam faced shoey operatively movable to releasesaidfcatch. means and thereafter to engage. the most frwardlbbd'y section. to release said tail gate and'nestfsaid. bod-ysections, sequentially, said actuation. means beingi operativelyrjoined toianddriveniby said .selectivespeed` transmission to correlate tlie rate. of. nestingto the vehicle. ground speed whendsired.-

3.- Adump. body, comprising. a. plurality of tele. scopic; body, sectionsl longitudinally movable. into a nested relationship, Va skirt secured. aboutv the periphery-oteachsaid sectionin slidableengagement Withthebody.. section telescopically com.- panion thereto, said. skirt serving., tospace .the Walls of; adjacent body sections. and to define therewith-a chamber,v then-side ot said chamber opposite; saidy skirt being. open to discharge -material. therethrough incooperation with.l the slidable engagement of vsaid lip, when.. said. body.- is. ex.- tendedaandactuation means-engaging. thelmedial portion of the mostfforwa-rd. of said.rnovable-body sections.,.tonnove.4 said dump` body, se1ectively,..to a. nested or anex-tended position.

4:. Atelescopic dump body,^ comprising. a. plurality of; complementary body sections of which` one-.isffixeda and. the. othersare longitudinally movablettonesttherein. each said section having.v two. side; Walls f joinedx by a: bottom member, and .a skirt-secured: about .the`r periphery of each. said. movable-section;- in:Y sldable .engagement with .the body; section. telescopicallyl` companion thereto, said; skirt-.servingto-` space'. the bottom. and side` Walls: of.y adjacent bodvl sections-and to. dene therewith a.- chamber, the` sideof` said.- chamber. opposite said. skirt being open.'4 .todischarge mate. rialr therethroughin' cooperationwith the. slidable. engagement of said. skirtfwhen. said body; is. extended. K l

52 Altelescopic dump-body,comprisinmaplurality of..'complmentar.y=. body.. sections of. which. one. ied'andlthe. others, are.lngitudi'r'iallfy.v movable to nest.'tliereineacl..said section .havig two side. Wallsjoinedby, abottom memb'en. a. single peripheral" skirt secured abouty the, side wallsandbbttom .of"eac" said'fmovable section in slidabi'engagementtwith the". inner' face'softliei bbttom` and sideY Walls'telscopicallyi'companion thereto, said skirt serving tospace'tliewalls of adi jacent body sections and to dene therewith an expansible' U-snaped cr'ramlcier4 and* actuation 12 meansengaging .the medial' :portionn of" the imost frwardlof' said' 'movable body sejctibnsitc moveA saidld'mp. body;- selectively;Y to i a-nest'ed' or ian' extendedpositon. n

6.A Incombinationgwith amotor vehicle having'v a. plurality of.'v telescopic" dump' body" sections? whicl. are mounted for seqii'iaritial'.Ylongitudinali movement to. and from a` nested. relationshipj ai movable-.tailgate mounted pivotally uponthe' rearmost telescopic dump.' bb'dy' section, catch' means movable selectively to latch and' to un" latcl' said taill gate, locking means engageablewith onei ofsai'd' dump. bod'y, sections andmovabl'e" to. lock and to .unlock the bodysecti'ons,y andactuL- ation means. including. a. shoe simultaneouslyiop.'` erable. upon. saidcatcliE means andE locking.h means to.un1atch .thetail gate andunlock thebod-ysec-v tions,. said actuation means. shoe thereafter and in sequencebeing engageable with the most'for- Wardy telescopio dump. body .section to move the'. same v.toward nested. relationship.

'7i .Incombinati-o'ns with amotor driven truck havingsa. selctivespeed transmission and carrying.. aplurality ofQtelescopic dump bodysect-onswhioh .are mounted for movement longitu-V dinally. of,the.truckA torandV from. a nested rela.- tionship, `a 4.movable tail. .gate .mounted pivotally. uponth'e rearmost.telescopicdump, body section.; catcnmeans movable .selectively .to la'ft'ch.r and. to." unlatchsaidtal. gate,.lcking..means movablegt'o. lock. and .tol unlock. said` body sections, and VYactu? ation. means.including...a.sioesimultaneously op.- erable. upon .said catch means andtlocking`-means. tounlatcn .the ta-ilv gate andl'unlock. .the body secetions, said actuation meanssh'oe thereafter. and. insequence being engageablevvith .thefmostffor- Ward.v telescopic.. d-ump .body .I section.` to. move^ the samey towardnested. relationship,. saidactuation. means beinggeared. to. anddrivenby said selecetive speed. transmission` to. correlate.. the Vrateofl nesting: ofthe. body sectionsxofthef ground speed,

othetruckwhen. desiredr R. FHELPS..

References Cited"n the file olthis'` patent.

UNITED STATES PATENTS 

